[kunai]

Doesn't seem like that far of a stretch given that Accutane (another acne medication) has been linked to IBD as well. There are a lot of drugs that interfere with the gut microbiota, of which its dysbiosis is often linked to the development of IBD. We're still in the infancy of understanding the pharmacokinetics of drugs as far as they relate to the gut and the ability of drugs to modulate the microbiome.

[jnwatson]

Isotretinoin and benzoyl peroxide are not remotely similar drugs. They have completely different mechanisms of action. That they both treat acne is essentially a coincidence.